Electrophotographic compositions and imaging processes are well known. In such processes, an electrophotographic element, having a photoconductive layer, is electrostatically charged and then imagewise exposed to form a latent electrostatic image. The latent electrostatic image is subsequently developed with a toner composition.
Various types of photoconductive insulating materials are known for use in electrophotographic imaging processes. In many conventional electrophotographic elements, the photoconductive insulating material is in a single layer composition affixed to a conductive support.
In addition, various multi-active electrophotographic elements (i.e. those having more than one active layer) have been described in the art. See e.g., U.S. Pat. No. 3,165,403 to Hoesterey. One layer, known as the charge generation layer, is affixed to the conductive support and generates charge carriers when exposed. Also present is a charge transport layer through which charge carriers which are generated in the adjacent charge generation layer pass in moving to the charged surface of the element.
Electrophotographic processes suffer from the deficiency of having to repeat the exposing step each time a copy is made. This is uneconomical and inefficient when producing multiple copies of a single document. As a result, photoelectrographic elements have been developed to produce multiple copies from a single exposure. See e.g., U.S. Pat. Nos. 4,661,429 and 3,681,066 as well as German Democratic Republic Patent No. 226,067 and Japanese Patent No. 105,260.
Acid photogenerators have been employed in photoelectrographic elements to be exposed with actinic or undefined radiation as shown, for example, in U.S. Pat. No. 3,316,088. Sensitizer dyes have been disclosed with regard to such elements, but not for sensitization in the near-IR portion of the spectrum. See, for example, in U.S. Pat. No. 3,525,612 and Japanese Patent No. 280,793.